Contactless switching device

ABSTRACT

A programmable switching device that employs a Hall Effect sensor and a moving magnet is disclosed. The Hall Effect sensor is electrically connected to a programmable microprocessor that is programmed to detect changes in Hall Effect voltages at the sensor. The programmable switching device may also be configured as a rotary switching device. By using a plurality of magnets and Hall Effect transducers and orienting some magnets with their polarities in different directions, a temper-proof switch can be achieved. The programmable switching device may be connected to a serial bus that is interfaced with an elevator controller.

FIELD OF INVENTION

[0001] The present invention relates to switching devices. Inparticular, the present invention provides a programmable contactlessswitching device that is particularly well suited for use in elevatorsystems.

DESCRIPTION OF RELATED ART

[0002] Push-button switches and rotary lever operated switches arecommon in many different systems. For example, elevator systems employnumerous push-button switches, as well as rotary, key operated switches.Typically, each elevator landing area employs hall call push-buttons.Each elevator car also employs a plurality of push-buttons for allowingpassengers to select those floors at which the car should stop and keyoperated rotary switches for use by elevator service personnel and firedepartments. Both the push-buttons and the rotary switches in the priorart employ mechanical contacts. For example, conventional push-buttonstypically use standard mechanically operated micro-switches, havingmechanical electrical contacts. Usually, the push-buttons contain one ormore fixed contacts and a movable conducting bridge that moves as thepush button moves, so that when the push button is depressed, the bridgeelectrically connects or disconnects the fixed contacts to form a closedor opened electrical circuit. Electrical wires connect the push-buttonsand the rotary switches to an elevator controller. By opening or closingan electrical circuit, the switches generate signals that can beinterpreted by the controller. One shortcoming of these mechanicalcontact switches is that, over time, the contacts and moving bridgeelements wear and can malfunction. For example, push-buttons often getstuck in a closed or opened position and there is no reliable method fordetermining when a push-button switch needs maintenance.

SUMMARY OF THE INVENTION

[0003] The present invention provides contactless programmable switchingdevices. These devices are particularly well-suited for use in elevatorsystems but may be used in other application that require switchingdevices. A programmable push-button device according to the presentinvention comprises a push-button element having an outer surface thatan elevator passenger can press with a finger. The push-button elementis linearly displaceable between at least a first and second positionand is biased toward the first position so that when displaced to thesecond position it returns to the first position. A magnet is mounted onpush-button element. A Hall Effect transducer is located in line withthe linear displacement direction of the push-button element. The HallEffect transducer is located such that when the push-button element isdepressed, the magnet moves closer to (or farther away) from thetransducer. The Hall Effect transducer is connected to a programmablemicroprocessor. The microprocessor is capable of being programmed with aunique address. A communication interface for linking the microprocessorto a central computer, such as for example an elevator controller, isconnected to the microprocessor.

[0004] The present invention may also be employed in a rotary switch. Inone embodiment, a plurality of magnets are mounted on a rotatable diskwith at least two having their polarities oriented in differentdirections. A plurality of Hall Effect transducers are located on asurface parallel to the disk. When the rotatable disk is in a firstposition a first set of the magnets is adjacent to the Hall Effecttransducers. As the disk rotates, a second set of magnets, some of whichhave their polarities oriented differently than those in the first set,becomes aligned over the Hall Effect transducers. The transducers areconnected to a microprocessor that can detect changes in the Hall Effectvoltages in the transducers. In this embodiment, the switch cannot beactivated by placing an external magnet near the device.

BRIEF DESCRIPTION OF THE FIGURES

[0005]FIG. 1 shows a programmable elevator push-button according to thepresent invention.

[0006]FIG. 2 illustrates a plurality of programmable contactless buttonsinterfaced with an elevator controller.

[0007]FIG. 3 illustrates an alternative embodiment of the presentinvention wherein an elevator controller assigns addresses to aplurality of programmable buttons in an elevator system.

[0008]FIG. 4 graphically illustrates a packet of information that may betransmitted to or from a programmable button.

[0009]FIG. 5 illustrates a contactless rotary switching device.

[0010]FIG. 6 is a top view of the rotary disk 100 shown in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

[0011] As is shown in FIG. 1, a contactless programmable push-button 1comprises a push-button element 2. The push-button element 2 has anexterior surface 3 and an interior mounting surface 5. The push-buttonelement 2 is linearly displaceable along a line 8 between a first andsecond position. The mechanical structure of the button and the relativelocations of the first and second positions may vary through the use ofconventional parts such as springs 18 and tabs 20 and 21. A magnet 10 ismounted to the interior surface 5. A Hall Effect transducer 15, such asOPTEK® Model OHS3150U (available from OPTEK, Inc. 1215 Crosby Rd,Carolton Tex., 75006), is mounted in line with the linear displacementdirection of the push-button element, i.e. the transducer is mountedalong the line 8. The spring 18 biases the push-button element 2 towardthe first position. When the push-button element 2 is depressed, themagnet 10 moves closer toward the Hall Effect transducer 15. As themagnet 10 moves toward the Hall Effect transducer 15, the Hall Effectvoltage in the transducer 15 changes and when the magnet 10 moves backtoward the first position the Hall Effect voltage changes back to itsoriginal state. This change in Hall Effect voltage is communicated to amicroprocessor 25 (such as the Microchip® 12C671, available fromMicrochip Tech., Inc. 2355 West Chandler Blvd, Chandler Ariz. 85224)that is interfaced with the Hall Effect transducer 15. In the event thatthe push-button element 2 sticks in the second position, themicroprocessor 25 can sense not only that the Hall Effect voltageincreased when the push-button element 2 moves from the first positionto the second position, but also that the Hall Effect voltage did notchange back to its initial value, thus indicating that the push-buttonelement 2 stuck in the second position. If a passenger frees thepush-button element 2, a change in Hall Effect voltage will occur as aresult of the magnet's change in displacement, and this can be detectedby the microprocessor 25. Moreover, even if partial movement of thepush-button element 2 is restricted or other damage or wear hasoccurred, a change in Hall Effect voltage will still occur. This changewill be detected and processed by the microprocessor 25 and in someembodiments, less than optimal performance will be noted by themicroprocessor 25.

[0012] The microprocessor 25 is configured to determine when thepush-button element 2 is depressed. A button press is defined as stepchange in the magnetic field measured over a brief period of time. Theperiod of time and the size of the step change are parameters that maybe programmed. Thus, these parameter can be optimized for eachapplication of a given push-button device.

[0013] The microprocessor 25 preferably has a One Time Programmable(“OTP”) memory. The sequence of operations that the microprocessor 25 isprogrammed to perform are stored in a memory. During initial programdevelopment, it may be advantageous to use devices with ErasableProgrammable Read Only Memory (“EPROM”). Software can be tested and thememory can be erased and reprogrammed to allow for changes thattypically become necessary during software development. Typically, EPROMdevices may be erased by exposing them to Ultraviolet (“UV”) radiation.To accommodate exposure to UV radiation, many erasable devices containquartz windows through which the UV radiation may pass. These “windowed”devices are relatively expensive, as a ceramic case is required to bondthe quartz window. Once the software has been developed and fullytested, a less expensive microprocessor—one not having a window—may beused. The microprocessor 25 preferably does not contain a window topermit UV radiation to erase the memory; hence it is a OTP memorydevice.

[0014] The microprocessor 25 may be programmed to read operationalparameters from tables at predefined locations within the OTP. Themicroprocessor 25 may be externally programmed via a programming device33. The programming device 33 may be an integral part of the push-button1 or may be externally connected to the push-button 1. The OTP memory ofthe microprocessor 25 may be reprogrammed a limited number of times andis not, therefore, only programmable once. For example, if the samplerate is a number from 1 to 255 and is stored as a byte in a tablebeginning at memory address 106 and the program is told the table ofentries is 20 entries long, the initial value is programmed at location106 and the remainder of the table from 107 to 125 is left in the erasedstate, having all ones. At a later point in time, the device may bereprogrammed to change the sample rate stored at location 106 to 0 and anew sample rate stored at location 107. The software would use the firstnon 0 value found in the table starting at 106 and continuing through125. This would permit reusing the device 20 times with different samplerates, even though an OTP memory microprocessor is used.

[0015] Preferably, but not necessarily, the microprocessor 25 is capableof being programmed after it is soldered to a circuit board. This allowsfor the manufacturing of generic push-button devices that can later beprogrammed for specific uses. The microprocessor 25 should also allowfor the changing of some or all parameters after initial programming.For example, the rate at which the microprocessor 25 looks at the HallEffect transducer 15 to determine the magnet position may be increasedor decreased to handle short or slow button presses more efficiently.This scan rate can be read from a table stored in the microprocessor'sprogram space. The program memory starts out with all bits programmed asa 1. When the device is programmed, the 1 bits are changed to 0. Tochange the scan rate, the memory location currently in use is programmedto all 0's and the next location is programmed to the new value. Themicroprocessor continues to read until a non 0 value is returned. Thenon 0 value is then used to determine the new scan rate.

[0016] The microprocessor 25 may use an averaging algorithm tocompensate for changes in quiescent Hall Voltage readings that resultfrom inexact placement of the magnet 10 and/or Hall Effect transducer15; variations in magnet field strength, which result from, among otherthings, variations in the magnet manufacturing process; and otherenvironmental changes, such as changing temperature. The averagingalgorithm may be a running averages algorithm. At each start up, a newaverage is accumulated for the transducer. The average is used as astart-up quiescent value. As time goes on, a running average ismaintained, and the running average is used to update the quiescentvalue.

[0017] The running averaging algorithm may operate as follows. Therunning average is set to zero each time the processor starts. The HallEffect voltage is averaged over a pre-selected minimum number ofsamples. Eight samples is usually satisfactory, but the minimum numberof samples may be higher or lower. If the minimum number of samplesneeded to generate an average is 8, the average will not be valid untilthe first eight samples are collected. As a ninth sample is collected,the running average is reduced by one eighth, and one eighth of theninth sample is added to the running average. As a tenth sample iscollected, the running average is reduced by one eighth, and one eighthof the tenth sample is added to the running average. This processcontinues so long as the microprocessor 25 is running. The runningaverage will reflect slow changes in the value caused by environmentalfactors. This running average will be used as the quiescent value andwill be compared to a current transducer reading to watch for a stepchange from the running average. A step change, will signal a buttonpush. If the button is jammed into a position part-way through the rangeof travel, the running average will take on a new value and still beable to detect a button push when a step change from this new runningaverage occurs. For example, if a vandal jambs a button in a depressedposition, the running average will be updated and the partiallydepressed position will become the new quiescent state. If there is anybutton travel remaining, subsequent button pushes will be reportednormally. The button may also report reduced functionality to thecontroller so as to indicate when maintenance is needed.

[0018] The microprocessor 25 may also be interfaced with acommunications interface 32 and a feedback device 28 that providesfeedback to the button operator. The feedback device 28 might take theform of LEDs that illuminate or might produce an audio signal. Thefeedback device 28 can either be incorporated into the button of thepresent invention or may be an external device.

[0019] As is shown in FIG. 2, a two wire RS485 bus 40 (which could be aLIN, CAN, or other multidrop bus configuration) connects a plurality ofpush-buttons 1 according to the invention to an elevator systemcontroller 45, which may be a computer or other device capable ofexecuting one or more instructions. The push-button devices 1 areconnected in parallel to the same wires and report a change in state viaa serial communications. The push-buttons 1 are polled by the controller45 at regular intervals and respond only when addressed.

[0020] The button 1 of the present invention may be programmed with aunique identification, or, alternatively, the system may assign uniqueidentification to each push-button 1 in the system. As is shown in FIG.3, an address wire 55 may be used to connect each push-button 1 to thecontroller 45. The address wire 55 runs from the controller 45 in andout of each push-button 1 in order from the first to last. The addresswire 55 is interrupted at each push-button 1 with an address switch 48that is controlled by each button's microprocessor. As a group ofpush-buttons is powered up, the address switch 48 in each push button 1(or within the microprocessor circuit of each button) defaults to anopen condition. Thus, only the first push-button, i.e. the push-buttonnearest the controller 45, will sense a signal from the controller 45.The first push-button takes the first address presented by thecontroller 45. The first push-button closes the address switch 48 andthe second push-button then senses a signal. The controller 45 presentsthe next address to the second push-button. The process continues untilno more push-buttons respond to the controller 45.

[0021] One advantage of having the system automatically assign uniqueaddresses is that each push-button may be manufactured as an identicaldevice and switches in an elevator system may be readily replaced withnew components. The new push-buttons would not need to be reprogrammedprior to installation. After new push-buttons are installed in anelevator system, the system may be powered up or a reset command sent bythe controller. The push-buttons wait for a command to assign them theirunique addresses. The address switch in each push-button defaults toopen on power-up or upon receiving the reset command. This breaks theaddress wire connection from one push-button to the next on the addresswire. As all of the push-buttons are in a reset state, they will respondto directed commands if the incoming address wire is high. Thus, if theincoming address wire is high and a push-button is in a reset state andthe command is an address command, then that push-button will beassigned the address in the address command. After that push-buttonreceives its address, the address switch closes and the next push-buttonis ready to receive its address. The controller can thus assign uniqueaddresses to all devices on the bus in order along the address wire.This feature allows the system to recover when a device is replaced or apower on or reset sequence is executed.

[0022] Communication on the bus 40 may take the form as shown in FIG. 4.Each device on the bus 40 is operating on a time base. There does notneed to be synchronization between the devices. When one device changesstate, the other devices on the bus 40 detect the change. The change isdetected by sampling the bus 40 at periodic intervals. Bit Time (“Bt”)is the time each bit will be present on the bus. It is dependent on thenumber of devices in the system and on how often they must be polled. Asis shown in FIG. 4, bits 8, 7, 5, 3 and 1 represent a high state andbits 0, 2, 4 and 6 represent low states. The default or resting state isa high state. Communications occur by sending a packet comprising astart bit, data bits, and a stop bit. Each bit is present for one Bttime. Each packet begins with a start bit, which is always a low bit.Eight data bits follow starting bit 0 and end with bit 7 (the completebyte). An address/command byte is identified by a high bit 8. A databyte is identified by a low bit 8. The 9 bits are followed by a Stopbit, which is always a high bit. The Start bit and Stop bit frame thepacket. The elevator controller samples the communication bus,preferably at least three times as fast as the Bt time.

[0023] Transmission of packets along the bus may occur as follows: Atransmitting device on the bus raises the bus to a high state for onebit or lowers the bus to a zero state for a zero bit, for one Bt timeperiod. A receiving device samples the bus three times during each Bttime period. The receiving device watches for the first transition onthe bus from a one to a zero, which marks the leading edge of a Startbit. Once the edge of the Start bit is located, the receiving deviceremembers this, and, if at the next sample, the bus is still a lowstate, the receiving device assumes that the transmitting device is inthe middle of sending a Start bit. Three samples later, the valuedetected by the receiving device will be the value of the 0 bit. Thevalue detected another three samples later, is the value of bit 1, andso on until the Stop bit is reached. If the Stop bit value is not a one,the packet will be discarded and the receiving device will wait untilthe bus is in the high state for two Bt times (6 samples in thisembodiment) and the process for detecting a Start bit will be repeated.

[0024] A Start bit is considered valid if it is detected at twosubsequent sample times. Once it is determined that the Start bit isvalid, collection of data bits may commence. Subsequent data bits aresampled a Bt time after a valid Start bit is detected. Samplingpreferably occurs as near the center of the Bt time as practical. Afterthe controller 45 sends data to a button, the controller 45 waits forsome time for a response. The response time will vary depending upon theBt time and the clock rate on the microprocessor 25.

[0025] Table 1 below represents some possible combinations of pollingrates, Bt time, number of packets exchanged and the number of devices ona bus. TABLE 1 1/Bt Polling Rate per second Packets per Exchange Devices300 2 6 25 300 4 6 12 300 10 3 10 300 8 4  8 9600  100 6 16

[0026] 1/Bt is defined by the following equation:

1/Bt=(polling times per second)*(Number of Devices)*(Packets perexchange+Reply wait packets)*(11 bits per packet)

[0027] The larger the Bt time, the less expensive the push-buttonmicroprocessor 25 and associated components. As noted above, if bit 8 isnot set, the packet is a data packet. If bit 8 is set, the packet is anaddress/command packet. Table 2 below represents command packets for 8devices. The device address is in bits 0-2 (address's 0-7). If bit 8 andbit 3 are set, this is a global packet destined for all push-buttons inthe system. The global command is represented in bits 4-8. If additionaldata is required, the address packet may be extended to more than onepacket. TABLE 2 Bit Position Command 8 7 6 5 4 3 2 1 0 0 x x x x x X x xData, the ninth bit is 0 1 0 0 0 0 1 X x x Global command 0 1 0 0 0 1 1X x x Global command 1 1 0 0 0 0 0 0 0 0 Command 0 (bits 4-7) to device0 1 0 0 0 1 0 1 1 0 Command 1 to device 6 1 1 0 0 0 0 1 1 1 Command 8 todevice 7

[0028] Global commands will not elicit a response from a button. Directcommands to a specific button will always have a response to confirmthat the button is active and functioning properly. The button willrespond with one or more packets of data. Because the system willtypically be a half duplex system, no two devices can send informationat the same time. One device sends and the other receives. After theinformation is received, the other device may then send information inthe form of a response.

[0029] The button can be illuminated to provide visual feedback to theoperator that the button press has been recognized. When the buttonmicroprocessor 25 recognizes a button press it lights the visualfeedback and reports the button press to the controller 45 at the nextpoll period. To overcome the possibility of noise causing an invalidbutton press signal, the button press is reported on the next poll aswell. The controller 45 only recognizes a valid button press if it issensed on two subsequent polls. The controller 45 sends a command to thepush-button on the next poll to tell the button to maintain theillumination. If the controller 45 fails to tell the button to maintainthe illumination, the button microprocessor 25 times out and turns offthe illumination providing visual feedback to the operator that thecontroller 45 has not accepted the button press.

[0030] In some embodiments, it may be desirable to install a soundmaking device on the same bus as the push-buttons and controller. Thesound making device may comprise a microprocessor, a sound chip (ISD149PLG), a speaker, and/or indicating lights. The sound chip storesrecorded sounds in an internal non-volatile memory. The microprocessor25 communicates on the bus as in the same manner as the push-buttons andgets its unique address in the same manner as the push-buttons. Thecontroller commands a specific Sound device at a specific address toplay a specific sound. This sound may be a recording of a gong, whichindicates an elevator has arrived or it may be a recorded voice saying“going down.” The controller may command the device to play a recordingsaying “out of service” or “fire service” or any other appropriatemessage as conditions may warrant. The controller may also command thedevice to light or to extinguish indicating lamps as necessary. Up anddown arrows can be illuminated as needed.

[0031] In addition, a position indicator can be connected to the bususing the same communication protocol as the push-buttons. The positionindicator may comprise a microprocessor and an LCD display screen, orother display device. The position indicator, like the push-buttons, isassigned a unique address and communicates on the bus in the same manneras the push-buttons. The controller commands a specific display on theLCD display screen, such as for example, a floor number.

[0032] The push-button device may operate in several different modes.For example, the push-button button device may be configured as an edgedetector, which detects the edges of the step function—i.e., when thepush-button element is initially depressed or when it is released. Thepush-button device may also operate as a level detector, which detectsthe portion of the step function between the edges—i.e., when thepush-button element is held in the depressed position. The detectionmode of the button may be changed dynamically as the system is inoperation. By adding this and other intelligence to the push-buttondevice, the controller 45 may contain less resources or use itsresources for other functions. In general, the more intelligent thepush-button device, the less intelligent the controller needs to be.Thus, the use of push-button devices allows for more efficient andcheaper systems.

[0033] While the push-button device is well suited for use in elevatorsystems, it may be used in any system that employs push-button switches.It may readily be adapted for use in explosive environments. Since thepush-button device contains no mechanical contacts, the electricalcomponents may be located in an explosion-proof housing and thepush-button element and magnet may be located outside the housing. Forexample, the electrical components can be located behind an aluminumplate, and the magnet and push-button element can be located in front ofthe plate.

[0034] The contactless switching device of the present invention maytake forms other than a push-button switch. As is shown in FIG. 5, acontactless switch may take the form of a lever operated rotary or keyoperated rotary switch, wherein the push-button element is replaced by arotary disk containing magnets. A rotary switch, unlike a singlemagnet/sensor combination switch, can be configured so that it cannot befooled by an external magnetic field that is stronger than the magnet inthe button. The rotary switch may use three Hall Effect transducers,150, 155, and 160 that are connected to a microprocessor 25. Thesetransducers are mounted on a planar surface 200. A first set of magnets,comprising magnets 115, 117, and 125, is mounted to a surface of arotary disk 100 that is parallel to the planar surface 200. The HallEffect transducers 150, 155, and 160 are located and aligned belowmagnets 115, 117, and 125, respectively, when the disk 100 is in a firstposition. The rotary disk 100 can rotate clockwise and counterclockwise. Additional magnets 110, 112, 120, and 122 are also mounted tothe surface of the rotary disk 100. As shown in FIGS. 5 & 6, thearrangement of the magnetic polarities is such that in each of the threepositions, the pattern of magnets detected by the three transducers isdifferent and all three of the magnets do not have their polaritiesoriented in the same direction. When the disk 100 rotates, a second setof magnets aligns over the transducers 150, 155, and 160. For example,if the disk 100 rotates clockwise to a second position, magnet 122aligns over transducer 155 and magnet 117 aligns over transducer 150 andmagnet 112 aligns over transducer 160. Since the all the magnets in thesecond set do not all have the same polarity orientation as the magnetsin the first set, the Hall effect voltages at at least one transducerchanges and when the Hall Effect voltage values stabilize, the newposition of the disk can be determined by the microprocessor 25.Moreover, since a rotary device may use a plurality of magnets havingtheir polarities oriented in different directions, an external magnetcannot fool the switch because the external magnet would bias allsensors in the same manner.

[0035] While the rotating switch embodiment described herein uses threemagnets, the number of magnets and their orientations may vary. The diskmay be rotated, for example, by a key or a lever. The actual manner inwhich the disk is rotated is not critical. Nor is it critical that thesensors be located directly over the magnets since the microprocessormay be programmed to detect changes in the magnetic fields acting on theHall Effect transducers.

[0036] It is also possible to configure a rotary device with one or moremagnets disposed on a rotating disk and one or more Hall Effecttransducers located on a planar surface that is parallel to the surfaceof the disk. As the disk rotates, the distance between the Hall Effecttransducers and the magnets vary. This causes the Hall Effect voltage inthe transducer to vary, and the change in Hall Effect voltages can beinterpreted by a microprocessor as a rotation of the disk. In someembodiments, mere rotation of a magnet relative to a Hall Effecttransducer may be sufficient to cause changes in the Hall Effect voltageat the transducer.

What is claimed is:
 1. A contactless push-button device comprising: apush-button element that is linearly displaceable between a firstposition and a second position and biased to move from the secondposition to the first position; a magnet mounted to the push buttonelement; a Hall Effect transducer mounted in line with the lineardisplacement direction of the push-button so that when the push-buttonmoves from the first position to the second position the distancebetween the magnet and the Hall Effect transducer changes; aprogrammable microprocessor for being assigned a unique address, theprogrammable microprocessor electrically connected to the Hall EffectTransducer;
 2. The contactless push-button device of claim 1, furthercomprising a plate mounted between the push-button element and the HallEffect Transducer.
 3. The contactless push-button device of claim 1,further comprising a feedback device that is electrically connected tothe microprocessor.
 4. The contactless push-button device of claim 1,further comprising a system controller that is interfaced with themicroprocessor, the controller assigning an address to the push-buttondevice during a start-up procedure.
 5. The contactless push-buttondevice of claim 1, wherein the microprocessor is programmed to contain aunique address.
 6. The contactless push-button device of claim 3 furthercomprising: a serial bus connected to the microprocessor; and anelevator controller connected to the serial bus.
 7. The contactlesspush-button switch of claim 6, wherein the serial bus is an RS 485 bus.8. A switching device comprising: a Hall Effect transducer; a movablemagnetic element that moves relative to the Hall Effect transducer; aprogrammable microprocessor electrically connected to the Hall Effecttransducer, the microprocessor programmed to execute a field averagingalgorithm to compensate for changes in quiescent Hall Effect voltages,the programmable microprocessor also programmed to contain a uniqueaddress; and a communication interface for connecting the microprocessorto a controller; the communication interface connected to themicroprocessor.
 9. The switching device of claim 8, wherein themicroprocessor is further programmed to detect when the magnetic elementmoves.
 10. An elevator system comprising: an elevator controller; aprogrammable contactless push-button device comprising: (i) a HallEffect transducer having a quiescent Hall Effect voltage; (ii) a movingmagnet located in line with the Hall Effect transducer, the movingmagnet being linearly displaceable along the line formed by the magnetand the Hall Effect transducer; and (iii) a microprocessor that isinterfaced with the Hall Effect transducer; the microprocessorprogrammed to calculate running averages for the quiescent voltage, themicroprocessor also having a unique address; and a serial bus connectingthe microprocessor to the elevator controller.
 11. The elevator systemof claim 10, wherein the microprocessor is further programmed to detectwhen the magnet moves.
 12. A contactless, rotary switch devicecomprising: a rotating disk having a surface; one or more magnetsdisposed on the disk; and one or more Hall Effect transducers located ona planar surface that is parallel to the surface of the disk, thedistance between the Hall Effect transducers and the magnets varying asthe disk rotates.
 13. The device of claim 12, further comprising aprogrammable microprocessor that is electrically connected to themicroprocessor.
 14. The device of claim 13, further comprising a systemcontroller that is interfaced with the microprocessor, the controllerfor assigning an address to the rotary switch device during a start-upprocedure.
 15. The device of claim 13, wherein the microprocessor isprogrammed to contain a unique address.
 16. The device of claim 13further comprising: a serial bus connected to the microprocessor; and anelevator controller connected to the serial bus.
 17. A switchcomprising: a plurality of Hall Effect transducers disposed on a planarsurface; a rotatable disk that is parallel to the planar surface; afirst set of magnets disposed on the disk, at least two magnets in thefirst set having their polarities oriented in different directions; asecond set of magnets disposed on the disk, at least two magnets in thesecond set having their polarities oriented in different directions; thedisk having a first position where one or more magnets in the first setis located over each Hall Effect transducer; and the disk having asecond position where one or more magnets in the second set is locatedover each Hall Effect transducer, and at least one transducer having amagnet over it with a polarity oriented differently than when the diskis in the first position.
 18. The switch of claim 17, further comprisinga microprocessor that is interfaced with the Hall Effect transducers.19. The switch of claim 18, wherein the microprocessor has a uniqueaddress.
 20. The switch of claim 19, further comprising a serial buswired to the microprocessor, the serial bus for connecting the switch toan elevator controller.